Jonathan Huynh wrote:
I have purchased Canon touch up paint for Canon on eBay.
used it to touch Canon 400mm F2.8L IS. with very good result.
make sure follow the instruction carefully.
See photo below.

Kathy, for repair of a tiny spot of missing paint, that ebay stuff is probably OK.

Larger areas of missing paint are much more difficult to recoat well. Then, you'd need the original Canon lacquer, and much patience. Furthermore, when using a paint brush it is near impossible to mimic the speckled finish of the original factory paint job .

Thanks for the info everyone, I will order the ebay stuff and give it a try. It is really a small speck on the bottom rim but I thought filling it in would keep it from getting worse. I don't think mine has yellowed much if any. I am really careful with my equipment, it really ticked me off when I did it.

pcho wrote:
I actually bought a tin of paint from canon. I then got a spray painter to spray on my 500mm and now I cannot see where the paint chip was. He did a great job for me. I highly recommend purchasing it.